<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
  <title>Title</title>
<!--  <link rel="stylesheet" href="stylesheets/reset.css">-->
  <link rel="stylesheet" href="stylesheets/index.css">
  <style>
    .weight {
      font-weight: bold;
      font-style: italic;
    }

    .text-danger {
      color: red;
    }
    .active {
      background-color: blue;
    }
  </style>
</head>
<body>

<div id="app">
  <h1 :class="[errorClass, isActive ? 'active' : '']">{{ msg }}</h1>
<!-- :class="{ active: isActive }" -->
<!--  :class="`weight ${isActive ? 'active' : ''}`"-->
  <!--
  <div
    class="weight"
    :class="{ active: isActive, 'text-danger': hasError }"
  >鹅鹅鹅，曲项向天歌!!!</div>
  <div
    class="weight"
    :class="classObj"
  >床天明月光!!!</div>

  <div
    class="weight"
    :class="classObject"
  >鹅鹅鹅，曲项向天歌!!!</div>
  -->
  <!--
  <div
    class="box"
    :style="`height: 200px; width: 200px; background-color: ${activeColor}; font-size: ${fontSize}px`"
  >
    box
  </div>
  <div
    class="box"
    style="height: 200px; width: 200px;"
    :style="{
      fontSize: fontSize + 'px',
     'background-color': activeColor
    }"
  >
    box
  </div>
  -->
  <div
    class="box"
    style="height: 200px; width: 200px;"
    :style="[styleObj, styleObj1]"
  >
    box
  </div>
  <button @click="isActive = !isActive; hasError = !hasError">change color</button>
</div>

<script src="js/vue.js"></script>
<script src="js/index.js"></script>
</body>
</html>
